Communication system optimized pooled line arrangement

Abstract

There is disclosed a communication system arrangement whereby the efficiency with which pooled facilities are used can be increased by reducing the number of lines that are dedicated to the pool. This is accomplished by making available to the pool, on a priority basis, lines that have been installed for other purposes, such as, for example, conference lines and private two-way lines. The system is arranged such that dedicated pooled lines have a higher priority than other lines which are available to the pool on a decreasing priority basis. In addition, each pooled set of lines at each station is given a visual indication using the system available lamp to indicate whether an idle line remains in the pool. This arrangement allows each station user to determine, without unnecessary seizure attempts, whether or not an available line exists in the pool.

What is claimed is: 
     
       1. A line pool control arrangement for use in a communication system having a plurality of stations, each station having access to any one of a number of lines serving said system by the momentary operation of a button at a telephone station set having a plurality of such buttons, said line pool control arrangement comprising means responsive to the enabling of certain ones of said buttons at each said station for enabling a communication connection to one line in a pool of said lines associated with said enabled button,   means for assigning a first priority to a set of said lines in said line pool such that when a pool line button is enabled at any said station only those idle lines in said set of lines having a first priority can become connected to said enabling station,   means for assigning a second priority to certain other of said lines outside said line pool such that when a pool line button is operated at any said station and all of said lines in said line pool set of lines are busy a communication connection is established to an available one of said other lines having said second priority.   
     
     
       2. The invention set forth in claim 1 further comprising means for assigning a third priority to certain of said other lines outside said pool such that when a pool line button is operated at any said station and all of said lines having said first or said second priority are busy a communication connection is established to an available one of said other lines having said third priority assigned thereto. 
     
     
       3. The invention set forth in claim 2 further comprising means for providing visual signals to all stations having button access to said pool of lines, and means for changing said visual signals such that when at least one such line is available a first indication will be given and when no lines in said set of pool lines are available a second indication will be given. 
     
     
       4. The invention set forth in claim 3 wherein said station buttons each have associated therewith a visual indicating device showing the enabled or released status of said button at said station, and wherein said visual signal means includes said status indicating device. 
     
     
       5. The invention set forth in claim 1 wherein said lines in said pool of lines having said first priority are each assigned a high to low priority from 1 to n, means within said 1 to n priority for determining an order of selection of a next available line by a central office, and   means controlled by said enabling of a pool line button at a station for connecting said station to a selected idle one of said lines in said pool, said selected idle line being determined in an order of selection with said 1 to n priority opposite to the order of selection of said central office line.   
     
     
       6. The invention set forth in claim 1 wherein said lines in said pool of lines are lines shared by several stations; and wherein said other lines are lines which are used as personal single lines.   
     
     
       7. In a communication system having a plurality of stations each having the capability of communicating with other stations over communication links internal to the stations as well as having the capability of communicating with stations external to the system over communication lines extended between the system and a central source, an arrangement for controlling pooled line access, said arrangement comprising means responsive to the enabling of certain ones of said buttons at each said station for enabling a communication connection to a pool of said lines associated with said enabled button,   means for assigning a first priority to a set of said lines in said line pool such that when a pool line button is enabled at any said station only those idle lines in said set of lines having a first priority can become connected to said enabling station,   means for assigning a second priority to certain other of said lines outside said line pool such that when a pool line button is operated at any said station and all of said lines in said line pool set of lines are busy a communication connection is established to an available one of said other lines having said second priority.   
     
     
       8. The invention set forth in claim 7 wherein said lines in said line pool are external lines. 
     
     
       9. The invention set forth in claim 8 wherein said lines in said other lines are all external lines. 
     
     
       10. The invention set forth in claim 9 further comprising means for assigning a third priority to certain of said other lines outside said pool such that when a pool line button is operated at any said station and all of said lines having said first or said second priority are busy a commmunication connection is established to an available one of said other lines having said third priority assigned thereto. 
     
     
       11. The invention set forth in claim 10 further comprising means for providing visual signals to all stations having button access to said pool of lines, and means for enabling said visual signals such that when no lines in said set of pool lines are available a visual indication is given. 
     
     
       12. The invention set forth in claim 7 wherein said lines in said pool of lines having said first priority are each assigned a priority from 1 to n, means within said 1 to n priority for determining an order of selection of a next available line by a central office, and   means controlled by said enabling of a pool line button at a station for connecting said station to a selected idle one of said lines in said pool, said selected idle line being determined in an order of selection with said 1 to n priority opposite to the order of selection of said central office line.   
     
     
       13. A communication system having a plurality of stations, each station having a plurality of buttons operable to establish communication connections to said station, and wherein each station has communication access to a number of lines, said system comprising means for grouping some of said lines into a first line pool,   means for grouping other of said lines into a priority set of lines,   means for assigning one of said buttons at at least one of said stations as a first pooled line access button,   means responsive to the enabling of said first pooled access button at any station having assigned thereto a first pooled line access button for enabling a communication connection between said station and a first available one of said lines in said line pool, and   means responsive to the enabling of said first pooled line access button at any station having assigned thereto a first pooled line access button for inhibiting said last-mentioned means and for enabling a communication connection between said station and a first available one of said lines in said priority set of lines when all of said lines in said first line pool of lines are determined busy.